1. Field of the Invention
The present invention relates to a feed roller unit having a feed roller which can abut against a topmost sheet of a stack of sheets, and rotate to separate the top sheet from the other sheets and convey the top sheet in a specific conveyance direction, and conveyance apparatus having the feed roller unit.
2. Description of the Related Art
There has been heretofore considered a feed roller unit having a feed roller which can abut against a top sheet of a stack of sheets, and rotate to separate the top sheet from the other sheets and convey the top sheet in a specific conveyance direction, and a driving force transmission unit for transmitting a driving force generated by a driving source to the feed roller so as to rotate the feed roller. In such a feed roller unit, the driving force generated by the driving source is transmitted to the feed roller through the driving force transmission unit so as to rotate the feed roller. Thus, the sheets such as recording paper retained in a stacked state can be conveyed, for example, toward a printer engine or the like, sequentially from the top one of the sheets.
In addition, in such apparatus, it is necessary to prevent a so-called multi feed in which two or more sheets lying on top of each other are conveyed together. To this end, there have been proposed techniques in which the feed roller is made eccentric to change a pressing force applied to the sheets (for example, see JP-A-2000-302258), or two kinds of pressing forces can be switched in accordance with the thickness of the sheets (for example, see JP-A-2003-146454).